Just noticed today on my MY01 with PPP that (especially in fourth) on just off full throttle that the boost does something weird...

It goes up to about 12/13 psi at about 2700/2800 revs then just at 3000 drops to 6.9 psi.... applying full throttle it then goes back up to about 20 psi by 3500 / 4000

Then knocklink is quiet but i did notice that at about this time on the SECS monitor the kock correction goes to 9.0 degrees???

Is there a problem is is it just the map? It is noticable (but only just and being as I;ve had the car 3 years it is subtle but noticable to me)...

 

does the vehicle have any kind of boost valve / bleed valve ?

 

Assuming you don't have a MBC, it's possible your wastegate solenoid needs cleaning.

 

No boost controller or bleed valve....

Solenoid eh? hmmm would that explain it only happening on part throttle positions were as on full throttle it's ok???

Anyhow.. off to do a search on solenoid cleaning....

 

What are you using to read the boost? If you are relying on the SECS monitor then you will find that it mis-reports boost on early PPP cars.

Mike

 

It would affect any throttle position that creates positive boost pressure. The fact you're hitting 20psi is pretty good proof that something somewhere is blocked/clogged. I don't know what the PPP max boost is, but it certainly isn't that high...

 

Mike... I have a seperate defi boost sensor fitted (from Psi 3) which is wired into the SECS monitor so it is showing true boost.

Judge.. the boost has always shown 20 psi and I have read before that is about the norm for a PPP car from previous posts I have read...

 

Are you sure about that? I can't speak for new age, but certainly the MY99/00 PPP boosted to around 16.5psi, just below fuel cut. 20psi would definitely trigger fuel cut on a classic...

 

Never had a problem with fuel cut just this happened in the last couple of days... Always read that much and that is PEAK and only reaches that between about 4 / 5 rpm then tails off

see http://bbs.scoobynet.co.uk/showthrea...+boost+reading i posted some time ago and http://bbs.scoobynet.co.uk/showthrea...+boost+reading

Thanks for your help though.. definatly going to clean pipes and solenoid...

 

Non-expert view


Are you saying the car is or feels slow as well as the boost indication or just that the boost does something funny? If the latter, surely this is correct? From what you say, it sounds like you have stopped accelerating and that is when the boost drops but climbs again when you floor it? That would sound normal to me as there is no longer the same load on the engine and you wouldn't see the same level of boost? For instance in lower gears, especially around town I actually see negative pressure as I have to lift slightly before changing otherwise the thing is just too damn quick (). Sorry if I'm confusing things it just sounds normal to me (assume SECS is digital display - all this is much easier to see on a nice big Defi ) oh and my 02 non PPP sti peaks at a smidge over 1.4 BAR (about 20.6 psi)

 

Not quite... throttle position is just of full ie 98% and is accellerating pretty hard then there is a drop off in accelleration with out my foot moving... it drops to 6.9 at the same revs in every gear UNLESS it's WOT......

 

Could it be a lambda sensor on the way out (the miltek although has a cat it is a sports cat and I do occasionally get a CEL P0420 because of this fact....

 

Wouldn't have thought a lambda sensor would cause this problem. Depending on gear and revs, even at 98% throttle, the fuelling would still be open loop, and therefore wouldn't be dependant on the lambda feedback.

It still sounds like a sticking wastegate solenoid...

 

well cleaned out the solenoid... no difference any other advice?

 

Fizz, how many times have you cleaned the solenoid, my MY01 took 2 attempts before it was working correctly.

I thought it was something else until i cleaned it again and all was fine.

Zippy

 

hmmm... second attempt coming up... basically the fluid was clear pipes clean as a whistle.... humph.. I'm beginning to think either dump valve or MAF

 

Also how loudly doe it click when green plugs are connected... couldn't even here it clicking yet alone feel it doing anything!!!

 

It should definitely be audible. Have another go at cleaning it. Empty a can of brake cleaner into it if you have to...!

 

Ok.. is it a rapid or slow click?

 

Fizz, dont bother with the Green connectors, take the Solenoid out and clean it off the car.You wont hear it click on an MY01 car.

Zippy

 

cheers zippy... I used quite a bit of cleaner but I still have the same problem.. I will try a second time but am not hopeful....

 

Hang on, yours is a new age? You don't have green connectors then, do you...?!

 

yep green connectors no black ones..... yup it is a new age... and yes connect them things start a whurring!!!! As said above MY01 PPP

 

I'll get me coat...

 

Sorry mate desperate to sort this out... I've got two days before the expense of the dealership is caled upon

 

Really bad now..it's as it cleaning the solenoid made it worse... off to clean it again.. is there anything else it could be.. plugs, coilpacks, lambda throttle position sensor, wastegate, dumpvalve

 

Fizz, have you cleaned ALL the pipes leading too and from the solenoid.

By that i mean removed them and cleaned them.On my first occasion this happened to me i had to remove ALL the pipes and clean them off the car.

I would be carefull about taking it to a main dealer as they probably wont have a clue.If it comes to it i would take it to a specialist as they will have seen this before, my local dealer took 8 hours plus to find out why my mates MY01 car wasnt boosting at all and only when i told them the actuator arm had probably come off they then found the fault, 10 minute fix and a new C washer and they where going to call in Subaru technical assist the following day,Ouch.

 

zippy,

yes... had all pipework off...

to be honest my dealer is pretty good (they run their own hill climb legacy and program the motek etc. on it)... they know what I have done and came to the same sort of conclusion about the solenoid. however it could actually be a failing solenoid as I completely lost boos twice on a track day in September... hmm wonder if it's the actuator

 

Wouln't have thought it would be the actuator. Even if the wastegate was permanently open, you'd still get boost. It would just take a hell of alot longer to build.

What about about the dump valve opening when it shouldn't? Or loose intercooler piping...?

 

good idea but would that be consitantly doing it at 2500 to 3000 rpm and only on part throttle???